Someone else may be able to provide better advice with your setup because it looks like you're at least halfway there - but I ran into problems configuring a WPA network manually as well, and ended up using the wicd configuration tool to do it automatically:

I had this problem for 2 frustrating days, when, after staring at the pi hopefully for around 10 solid minutes, I realized that the wifi must have some power draw. I checked the power supply I was using, and it was 5v 550ma. I changed it to one that supplies 1000ma, and thus far the problem is fixed.

For reference, my original problem was that periodically, and usually when the wifi was being used, the gui would crash and I would get the message that it couldn't get the status from the wpa_supplicant.conf file

I had tried virtually every variation of the conf files that I could find, modified the /etc/network/interfaces file, used "sudo /init.d/networking stop" then restarted with "sudo /init.d/networking start", and on and on.

I also tried the following:
sudo ifup --force wlan0

It would force the wpa_gui to read the conf file, but it would not get an IP address. To me, this said that everything on the software side of things was working (if only for that instant), that it was a hardware issue. I checked to make sure my router wasn't booting me off the network, and that didn't seem to be the case.

Then added my networks security information (you will need to replace networkssid with the SSID of your network and passphrase with the security passphrase). Usually your WiFi security would be on a sticker on the back of the router.